The invention concerns a block suction apparatus for fixing plate-shaped work pieces on a fixing beam or fixing table using under-pressure, wherein at least one contact surface of the block suction apparatus comprises a sealing plate with a sealing lip at its periphery, wherein the sealing lip delimits a suction chamber, wherein at least one supporting element is provided within the suction chamber.
Block suction apparatus are generally known and are used for fixing and clamping plate-shaped work pieces on processing machines. These processing machines have fixing beams or a fixing table, with several block suction apparatus usually being disposed on several fixing beams or a fixing table, and the plate to be processes is disposed on the block suction apparatus. The plate is held for processing on the block suction apparatus through under-pressure. For under-pressure fixing of the work piece, the block suction apparatus comprises a sealing plate, which has a sealing lip delimiting a suction chamber. When this suction chamber is subjected to under-pressure, the plate is suctioned thereby changing the separation between plate and block suction apparatus. To obtain a defined position of the plate relative to the block suction apparatus and therefore relative to the fixing beam or fixing table, the block suction apparatus has at least one supporting element on which the work piece or the plate abuts after suction, and is thereby aligned relative to the fixing beam or the fixing table at a position relative to the block suction apparatus which cannot change.
Especially for large work pieces, when the edges of the work pieces greatly jut out, or when a relatively small number of block suction apparatus are used, the orientation of the plate-shaped work piece relative to the fixing beam or the fixing table is insufficient.
It is therefore the underlying purpose of the present invention to provide a block suction apparatus, which permits improved and more exact positioning of the work piece.
This object is achieved in accordance with the invention with a block suction apparatus of the above-mentioned type in that at least one additional supporting element is provided which is located in the direct vicinity of the sealing lip.
The inventive block suction apparatus comprises an additional supporting element, which is disposed close to the edge and close to the sealing lip. This is advantageous in that a section of the plate projecting past the block suction apparatus is supported in as optimum a fashion as is possible with the block suction apparatus. Sagging of the section of the plate projecting past the block suction apparatus is thereby reduced and the edge of the plate can therefore be processed with greater accuracy.
In a further development, the additional supporting element is located in the region of a corner of the contact surface. In particular, the projecting corner-regions of the plate, which are relatively instable, are thereby supported by the additional supporting element of the inventive block suction apparatus and are aligned with the fixing beam or fixing table.
In a preferred embodiment, several additional supporting elements are provided. They are preferably located in the corner regions of the sealing plate such that the block suction apparatus has equally good supporting properties in all directions.
These several additional supporting elements are preferably uniformly distributed over the contact surface. In particular, the additional supporting elements form a uniform grid together with the conventional supporting elements, in particular along parallel lines.
The sealing plate has an opening for the additional supporting element, which provides passage of the supporting element through the sealing plate. This opening is fashioned to terminate on the supporting element in a sealing fashion to prevent leaking air from being suctioned through this opening.
To prevent slippage of the plate towards the block suction apparatus, the invention provides that the sealing plate has a base plate comprising the opening and a bead, wherein the bead protrudes beyond the base plate and surrounds the opening. This bead optimally supports the base plate against lateral displacement on the additional supporting element. The bead projects past the additional supporting element in the direction towards the work piece such that the work piece abuts the bead and the bead holds the work piece. The bead consists of compressible elastic material and the projecting part of the bead is compressed when the work piece is suctioned until the work piece abuts the supporting element. The bead that consists of a slip-reducing material abuts with a predetermined force on the work piece and prevents displacement of the work piece relative to the block suction apparatus. The additional supporting element preferably has the shape of a pin. A cylindrical pin shape is advantageous in that the opening in the base plate may be circular to provide simple sealing and facilitate production of the additional supporting element.
Further advantages, features and details of the invention can be extracted from the dependent claims and the following detailed description of a particularly preferred embodiment with reference to the drawing. The features shown in the drawing and mentioned in the claims and in the description may be essential to the invention either individually or collectively in arbitrary combination.